Diving bells have long been known for underwater utility. They typically have consisted of a spherical hull in or from which a crew of men may work or from which a crew may observe the surrounding water or terrain, depending upon whether the diving bell is a lock-out bell or an observation bell.
In a lock-out bell, an air-lock provides the necessary interior pressure so that an opened bottom portion of the diving bell may be employed through which a crew of men may have access to the surrounding water. In an observation bell, the hollow hull is provided with small clear windows by which limited observation of the surrounding water may be effected for whatever particular pupose desired.